Two ambulance vehicles were called to the railway station after a female passenger became unwell between Havant and Chichester.
Southern Rail tweeted: “Due to a passenger being taken ill on a train between Havant and Chichester, platform one at Chichester is currently blocked. Services from Havant are currently unable to run towards London/Brighton past Chichester station.”
A spokesman for South East Coast Ambulance Service said: “We were called at around just after 1.40pm this afternoon to platform one of the station at Chichester to reports of a female who was unresponsive and in need of medical attention.
“One ambulance and one other vehicle attended the scene.
“The female patient was treated at the scene and taken to St Richard’s Hospital for further treatment.”
The line has since cleared with trains now running to time according to Southern.
They later tweeted: “Disruption between Havant and Chichester has now ended.”